<div dir="ltr">You can actually find 12->5v step downs locally in NZ for cheap enough. All car USB converters do exactly this, and can be had on trademe for a couple dollars: <a href="https://www.trademe.co.nz/computers/cables-adaptors/usb/listing-2220387680.htm">https://www.trademe.co.nz/computers/cables-adaptors/usb/listing-2220387680.htm</a><br>If you have a dollar-store-thing near you, they probably have them as well for $4-5. In bishopdale mall there's a "Party Dollar Store" that I used to pick up this sort of thing from. <div><br></div><div>Even if you're not using it in the cabin of the car, you can open it up and extract the PCB so you can solder wires to it. The ones I used had a single screw that held the whole thing together.<br><br>Is the output stable? Well, from a clean 12V supply, I've been running a raspberry pi for the past two years, and it's still working. No idea about what a racecar would do to it.</div><div><br></div><div>Geoff</div></div><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">On Sun, Jul 7, 2019 at 5:15 AM <<a href="mailto:m.beckett@amuri.net">m.beckett@amuri.net</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><u></u>
<div style="font-family:Verdana,Geneva,sans-serif">
<p>+1 on the insulated.</p>
<p>The vibration will range from fairly solid thumps to higher frequency vibration, so rubber isolation will be your frend.</p>
<p>Large components will appreciate a dab of a neutral cure silicon to help them hold in place rather than relying on the component leads.</p>
<p> </p>
<p>The electrical noise is not likely to be any more than a normal car. Race cars tend to have lower amperage alternators and the battery while smaller is not as taxed as a normal car.</p>
<p>Choke and capacitor (both large uF and smaller 0.1uF) across the incoming should be enough.</p>
<p>You can have someone check the 5v line with an oscilloscope if you have any doubts.</p>
<p> </p>
<p>cheers</p>
<p>Mark</p>
<p> </p>
<p>On 2019-07-07 13:32, Mark Atherton wrote:</p>
<blockquote type="cite" style="padding-left:5px;border-left:2px solid rgb(16,16,255);margin-left:5px">
<div class="gmail-m_-7769425318177214365moz-cite-prefix">Hi Daniel,</div>
<div class="gmail-m_-7769425318177214365moz-cite-prefix"> </div>
<div class="gmail-m_-7769425318177214365moz-cite-prefix">First on your list would be my first choice, only because of the size of the regulator :) Also appears to be available on Trademe for a few-more-bucks <a href="https://www.trademe.co.nz/Browse/Listing.aspx?id=2212079583" target="_blank">https://www.trademe.co.nz/Browse/Listing.aspx?id=2212079583</a>Datasheet for the XL6009 part is <a class="gmail-m_-7769425318177214365moz-txt-link-freetext" href="https://www.sunrom.com/get/283300" target="_blank">https://www.sunrom.com/get/283300</a> indicates that the part is up to 94% efficient, and has a wide input range - 5-32V. Power spikes on car 12V rails can be quite large, so having a regulator that can tolerate a 32V spike is heading in the right direction.</div>
<p>As Volker says, mechanical vibration can be a killer; all components need to be well secured; screwing or gluing modules to an insulated substrate may work well.</p>
<p>Looks like a great project, links to photos of the project / vehicle appreciated.</p>
<p>Regards,</p>
<p>Mark</p>
<div class="gmail-m_-7769425318177214365moz-cite-prefix">------------------</div>
<div class="gmail-m_-7769425318177214365moz-cite-prefix"> </div>
<div class="gmail-m_-7769425318177214365moz-cite-prefix">On 7/07/2019 9:04 AM, Daniel Powell wrote:</div>
<blockquote type="cite" style="padding-left:5px;border-left:2px solid rgb(16,16,255);margin-left:5px">
<div class="gmail-m_-7769425318177214365WordSection1">
<p class="MsoNormal"><span>Sorry for the intrusion with something bound to be a simplistic and rather rudimentary question given my lacklustre knowledge in electronics. </span></p>
<p class="MsoNormal"><span> </span></p>
<p class="MsoNormal"><span>I’m currently developing an ESP32 wrover, CAN Bus based dash for my race and rally car. I’ve already prototyped the dash using a Nano (which was too slow to capture every frame), then prototyped all but the 7 segments using the ESP32 (7 segments are 5v LL, ESP is 3.3). I’ve recently transferred it to protoboard (which I’m simply using as a flat substrate to level and mount the modules). I need to reliably convert the car 12v to the 5 volt required for VCC on most of my devices. I’ve purchased a handful of different aliexpress 3A DC to DC voltage stepdown regulators and a 1.8A buck converter. </span></p>
<p class="MsoNormal"><span> </span></p>
<p class="MsoNormal"><span>I wondered, given the noisy power environment of a race car, which, if any, would be best to provide 5v to my dash. </span></p>
<p class="MsoNormal"><span> </span></p>
<p class="MsoNormal"><span>Unfortunately my pics break the 40k email list limit, as such I’ll include links to the devices. </span></p>
<p class="MsoNormal"><a href="https://www.aliexpress.com/item/32280431843.html" target="_blank">https://www.aliexpress.com/item/32280431843.html</a> , <span style="font-size:9pt;color:rgb(153,153,153);background:white"> LM2596HVS, XL4005 and </span><span style="font-size:9pt;color:black;background:white"> </span><span class="gmail-m_-7769425318177214365sku-title-value"><span style="font-size:9pt;color:rgb(153,153,153);background:white">XL7015</span></span></p>
<p class="MsoNormal"><a href="https://www.aliexpress.com/item/32961984080.html" target="_blank">https://www.aliexpress.com/item/32961984080.html</a> , <span style="font-size:9pt;color:rgb(153,153,153);background:white"> 12V LM7812</span></p>
<p class="MsoNormal"><a href="https://www.aliexpress.com/item/32921703886.html" target="_blank">https://www.aliexpress.com/item/32921703886.html</a></p>
<p class="MsoNormal"><span> </span></p>
<p class="MsoNormal"><span>I’ve previously used a radio control UBEC to convert the car power to something I could pump into a raspberry pi, through it’s on board conditioning, however I’ve never bothered to understand the fundamentals of power supply or how to smooth it such that I don’t damage componentry. </span></p>
<p class="MsoNormal"><span> </span></p>
<p class="MsoNormal"><a href="https://www.aliexpress.com/item/32920672534.html" target="_blank">https://www.aliexpress.com/item/32920672534.html</a></p>
<p class="MsoNormal"><span> </span></p>
<p class="MsoNormal"><span> </span></p>
<p class="MsoNormal"><span>Help genuinely appreciated. <br><br> For those of you interested and wishing to punish yourselves further. <br> TTGO ESP32 wrover (on board CAN) </span></p>
<p class="MsoNormal"><span>NS65HVD230 CAN transceiver. </span></p>
<p class="MsoNormal"><span>MAX2719 8x8 matrix (gear display)</span></p>
<p class="MsoNormal"><span>4 x TM1637 - 7 segments (switched pages of 4 pressures/temps/alerts)</span></p>
<p class="MsoNormal"><span>2 x 8 WS2812 Neopixles. (RPM and colour change for alerts). </span></p>
<p class="MsoNormal"><span>TXS018E 8 channel logic level converters (yet to test). </span></p>
<p class="MsoNormal"><span> </span></p>
<p class="MsoNormal"><span>Regards, <br> Daniel Powell. </span></p>
<p class="MsoNormal"><span> </span></p>
<p class="MsoNormal"><span> </span></p>
<p class="MsoNormal"><span> </span></p>
<p class="MsoNormal"><span> </span></p>
</div>
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